ANALOG DEVICES ADM1232 Service Manual

Microprocessor

T

V5V

FEATURES

Pin-compatible with MAX1232 and Dallas DS1232
Adjustable precision voltage monitor with 4.5 V and

4.75 V options

Adjustable strobe monitor with 150 ms, 600 ms, or

1.2 sec options
No external components
Specified from −40°C to +85°C

APPLICATIONS

Microprocessor systems
Portable equipment
Computers
Controllers
Intelligent instruments
Automotive systems

GENERAL DESCRIPTION

The ADM1232 is pin-compatible with the MAX1232, DS1232LP,
and DS1232. The Analog Devices, Inc., ADM1232 is a micro­processor monitoring circuit that can monitor the following:

• Microprocessor supply voltage

• Whether a microprocessor has locked up

• External interrupts

The ADM1232 is available in four packages: an 8-lead MSOP
(RM-8), an 8-lead PDIP (N-8), a 16-lead wide SOIC (RW-16),
and an 8-lead narrow SOIC (R-8).

V

CC

OLERANCE

PB RESET

TD

GND

GND TD TOLERANCE

Supervisory Circuit

ADM1232

FUNCTIONAL BLOCK DIAGRAM

5%/10%

TOLERANCE

SELECT

RESET

VREF

DEBOUNCE

WATCHDOG

TIME-BAS E

SELECT

Figure 1.

5

10kΩ

ADM1232

STROBE

RESET

Figure 2. Typical Supply Monitoring Application

GENERATOR

WATCHDOG

TIMER

ADM1232

MICROPROCESSOR

I/O

RESET

RESET

RESET

STROBE

07522-002

7522-001

Rev. C

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©1997–2008 Analog Devices, Inc. All rights reserved.

ADM1232

TABLE OF CONTENTS

Features .............................................................................................. 1

Applications ....................................................................................... 1 

Functional Block Diagram .............................................................. 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications ..................................................................................... 3

Absolute Maximum Ratings ............................................................ 4

Thermal Resistance ...................................................................... 4

ESD Caution .................................................................................. 4

REVISION HISTORY

12/08—Rev. B to Rev. C

Updated Format .................................................................. Universal

Changes to Table 2 ............................................................................ 4

Added Thermal Resistance Section ............................................... 4

Updated Outline Dimensions ......................................................... 7

Changes to Ordering Guide ............................................................ 9

12/97—Rev. A to Rev. B

Changes to Specifications Section .................................................. 2

x/97—Rev. 0 to Rev. A

Changes to Specifications Section .................................................. 2

7/97—Revision 0: Initial Version

Pin Configurations and Function Descriptions ............................5

Circuit Information ...........................................................................6

PB RESET

STROBE

Tolerance ........................................................................................6

RESET and

Outline Dimensions ..........................................................................7

Ordering Guide .............................................................................9

.......................................................................................6

Timeout Selection .........................................................6

RESET

Outputs .........................................................6

Rev. C | Page 2 of 12

ADM1232

SPECIFICATIONS

VCC = full operating range, TA = T

Table 1.

Parameter Min Typ Max Unit Test Conditions/Comments

TEMPERATURE −40 +85 °C TA = T
POWER SUPPLY

Voltage 4.5 5.0 5.5 V

Current 20 50 μA VIL, VIH = CMOS levels.
200 500 μA VIL, VIH = TTL levels.
STROBE AND PB RESET INPUTS

Input High Level 2.0 VCC + 0.3 V

Input Low Level −0.3 +0.8 V
INPUT LEAKAGE CURRENT

(STROBE, TOLERANCE)

TD 1.6 μA
OUTPUT CURRENT

RESET 8 10 mA VCC is at 4.5 V to 5.5 V.

RESET/RESET

OUTPUT VOLTAGE

RESET/RESET

RESET/RESET High Level

RESET/RESET Low Level

1 V OPERATION

RESET Output Voltage VCC − 0.1 V When sourcing less than 50 μA.

RESET Output Voltage

VCC TRIP POINT

5% 4.5 4.62 4.74 V TOLERANCE = GND.

10% 4.25 4.37 4.49 V TOLERANCE = VCC.
CAPACITANCE

Input (STROBE, TOLERANCE)

Output (RESET, RESET)

PB RESET

Time 20 ms

Delay 1 4 20 ms
RESET ACTIVE TIME 250 610 1000 ms

STROBE

Pulse Width 70 ns

Timeout Period 62.5 150 250 ms TD = 0 V.
250 600 1000 ms TD = floating.
500 1200 2000 ms TD = VCC.
VCC

Fall Time 10 μs Guaranteed by design.

Rise Time 0 μs Guaranteed by design.
VCC FAIL DETECT TO RESET

OUTPUT DELAY

50 μs After VCC falls below the set tolerance voltage (see Figure 9).
250 610 1000 ms After VCC rises above the set tolerance voltage.

MIN

to T

, unless otherwise noted.

MAX

MIN

to T

MAX

.

−1.0 +1.0 μA

−8 −12 mA V

V

− 0.5 VCC − 0.1 V

CC

is at 4.5 V to 5.5 V.

CC

When sourcing less than 500 μA, RESET remains within

0.5 V of V

on power-down until VCC drops below 2.0 V.

CC

When sinking less than 500 μA, RESET remains within

0.5 V of GND on power-down until V

0.4 V

2.4 V

0.1 V When sinking less than 50 μA.

5 pF T
7 pF T

= 25°C.

A

= 25°C.

A

PB RESET

must be held low for a minimum of 20 ms to

guarantee a reset.

RESET and RESET

are logically correct.

drops below 2.0 V.

CC

Rev. C | Page 3 of 12

ADM1232

ABSOLUTE MAXIMUM RATINGS

TA = 25°C unless otherwise noted.

Table 2.

Parameter Rating

VCC 5.5 V
Logic Inputs −0.3 V to VCC + 0.3 V
Storage Temperature Range −65°C to +150°C
Lead Temperature (Soldering, 10 sec) 300°C

Vapor Phase (60 sec) 215°C
Infrared (15 sec) 220°C

Power Dissipation

N-81 1000 mW
RW-16, RM-82 900 mW
R-82 900 μW

1

Derate by 13.5 mW/°C above 25°C.

2

Derate by 12 mW/°C above 25°C.

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

THERMAL RESISTANCE

θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.

Table 3. Thermal Resistance

Package Type θJA Unit

8-Lead PDIP (N-8) 100 °C/W
16-Lead SOIC_W (RW-16) 73 °C/W
8-Lead MSOP (RM-8) 206 °C/W
8-Lead SOIC_N (R-8) 153 °C/W

ESD CAUTION

Rev. C | Page 4 of 12